LIBRARY OF CONGRESS. 

Shelf. _?>" 7 

UNITED STATES OF AMERICA. 





■ 



•*i 





THE MYOLOGY of the PIGEON 

(COLUMBA LIVIA) 

A Study of the Muscular System of 
the Pigeon 



BY 



CHARLES M. BURK, M. D. 

INSTRUCTOR IN ZOOLOGY IN THE UNIVERSITY OF PENNSYLVANIA 



PHILADELPHIA 

1893 



JUN'ib 1893 



•^ 






Entered, according to Act of Congress, in the year 1893, by 

CHARLES M. BURK, 

In the office of the Librarian of Congress, at Washington, D. C. 



QL6^7 



INTRODUCTION 



That the pigeon has a well-developed muscular 
system is shown by its rapid and sustained flight. 
These birds have been killed in New York whose 
crops contained undigested grains of rice that must 
have been swallowed in North Carolina or Georgia 
not long before. We are also familiar with their 
use as carriers of messages, in which their speed 
has been carefully and accurately timed and found 
to be truly remarkable. These and other instances 
of rapid flight and long endurance are accounted 
for when we come to inspect the muscles of flight 
and observe how well adapted they are by 
structure and development for that purpose. The 
pigeon, therefore, makes a very good subject for 
laboratory work when it is desired to dissect a 
representative of the order Avis. 

In this sketch of the myology of the pigeon, the 
muscles are grouped in the following manner. 
Beginning with the muscles of the head, those 
which perform the movements of the mandible, ear 
and eye are described. In the next group the 

(3) 



4 INTRODUCTION. 

muscles of the neck are dissected. In successive 
order the following groups are described. Those 
of the pectoral extremity, of the shoulder girdle 
and arm, of the hand, of the thorax and abdomen, 
of the trunk and thigh, of the front of the leg, of 
the back of the leg, and lastly the muscles of the 
tail. 

Under the heading of each group a list of the 
muscles found in the group is given. It is hoped 
that this orderly discussion will assist the student 
not only in the work of dissection, but also in the 
more important end of acquiring a clear idea of the 
relative position of the several parts which go to 
make up the muscular system. 

Before the student begins the study of the 
myology of the pigeon he should be thoroughly 
familiar with its osteology, an outline of which 
will be found in Dr. T. J. Parker 1 s Zootomy (ver- 
tebrata). 



Myology of the Pigeon. 



MUSCLES OF THE HEAD. 

In this group will be found the muscles which 
have to do with the movement of the lower jaw, 
eye, ear, and tongue. In removing the skin of the 
head, the first muscle which makes its appearance 
is the Platisma Myoides, which closely adheres to 
the skin. After the removal of this, the muscles 
of the lower jaw are most prominent. These con- 
sist of the 

Masseter. 

Temporal. 

Digastric. 

En to-tympanic . 

Pterygoides internus. 

Pterygoides externus. 
Platisma Myoides is a thin sheet of muscle 
found immediately beneath the skin. It covers the 
posterior and lateral portions of the head and has 
its origin in either side of the head, arising from 
that portion of the frontal bone which forms the 

5 



6 MYOLOGY OF THE PIGEON. 

posterior boundary of the orbital cavity, and also 
from the squamous portion of the temporal. From 
this origin, the fibres on either side pass backward 
and inward and meet at the point where the head 
joins the neck. The continuation of the muscle 
passes backward, covering the back and sides of the 
neck, and adhering closely to the skin into which it 
finally inserts. The fibres of the muscle, near its 
origin, are also attached to the skin of the external 
ear. 

Masseter. — This is a small muscle' situated just 
in front of the orifice of the ear. It arises from the 
outer surface of the squamosal bone and passes 
obliquely downward and forward, and as it 
approaches the jugal bone it gives off a delicate 
tendon which passes over the outside of the jugal 
to insert into the articular portion of the mandible. 
The main portion of the muscle then passes on the 
internal side of the jugal to insert into the stipra- 
angular portion of the mandible. The function 
of this muscle is to raise the lower jaw. 

Temporal. This muscle is only exposed by care- 
fully removing the entire eyeball. It arises by two 
sets of muscular fibres. The first portion arises from 
the base of the alisphenoid. The second portion 
arises from the upper surface of the paletine 



MUSCLES OF THE HEAD. 7 

and pterygoid bones. Both portions form a com- 
mon insertion into the internal surface of the supra- 
angular portion of the mandible. The function of 
this muscle is to close the lower jaw and to hold 
it firmly to its articulation. 

Digastric. — This muscle has two distinct por- 
tions. The first portion arises from the exoccipital 
region of the skull, and passes obliquely downward 
and forward to insert into the posterior surface of 
the articular bone of the mandible. The second por- 
tion is entirely covered by the first portion, and 
arises from the tympanic portion of the squamosal ; 
from thence it passes directly to the articular bone 
of the mandible. It is the first portion of this 
muscle that is illustrated in Fig. 1. 

EnTO-Tympanic is a small muscle situated at the 
base of the skull, the function of which is to raise 
the pterygoid region. It arises froirrthe rostrum and 
basi-sphenoid and passes backward to be inserted 
into the pterygoid and quadrate of the same side. 

Pterygoides InTERNUS is a large muscle situ- 
ated at the base of the cranium, arising from 
the palatine, sphenoidal rostrum, and pterygoid, 
and inserting into the inner surface of the 
ramus of the mandible as far back as the articular 
bone. 



8 MYOLOGY OF THE PIGEON. 

Pterygoides Externus. — This is smaller than, 
and concealed by, the preceding. It arises from the 
quadrate and pterygoid bones. It runs forward and 
outward to be inserted on the inner surface of the 
mandibular ramus. 



MUSCLES OF THE TONGUE. 



MUSCLES OF THE TONGUE. 

These consist of certain muscles which are at- 
tached to the hyoid apparatus, and perform the 
different movements of the tongue. They consist 
of the 

Mylo-hyoid, 

Stylo-hyoid, 

Genio hyoglossus, 

Cerato-hyal, 

Depressor-glossi. 
Mylo-hyoid is a very delicate set of muscle 
fibres arising on either side from the anterior half 
of the lower margin of the jaw. The fibres from 
either side run transversely across to join in a 
median raphe. This muscle really forms the floor 
of the mouth, and supports the lingual and hyoid 
apparatus. 

Stylo- hyoid. — This is a delicate slip of muscle 
which is seen lying on the outer side of the face. 
It arises from the external surface of the articular 
bone of the mandible, and passes to be inserted 
into the cerato-branchial of the thyro-hyal. When 
this muscle contracts it pulls the tongue to one 
side. 



IO MYOLOGY OF THE PIGEON. 

Genio-hyogix>ssus. — This is the largest of this 
group. It arises from the internal surface of the 
mandible at about the middle. The fibres form a 
flat band of muscle which passes obliquely down- 
ward and backward until it reaches the thyro-hyal, 
around which it courses and which it envelopes 
back to its posterior extremity. The function of 
this muscle is to thrust the tongue from the mouth. 

Cerato-hyal is a slender muscle covering the 
thyro-hyal, along which it passes, following the 
course of the thyro-hyal and adhering to the hyoid 
until it reaches the uro-hyal, into which it is in- 
serted. This muscle has also the function of mov- 
ing the tongue to one side. 

Depressor-glossi is an azigos or single muscle, 
and the smallest of the tongue muscles. It 
arises from the ventral surface of the basi-hyal 
and passes directly forward to the glosso-hyal. 
The function of this muscle is to depress the tip 
of the tongue and to elevate the base. 



THE MUSCLES OF THE EYE. II 



THE MUSCLES OF THE EYE. 

It is advisable to leave the dissection of these 
muscles until after the dissection of the neck. 
For, in order to see them, a large portion of the 
skull must be cut away. The muscles of the eye 
in the pigeon consist of those muscles which per- 
form the movements of the eyelids and ball. They 
are the 

Orbicularis palpebrarum, 

Pyramidalis nictitans, 

Obliquus superior, 

Obliquus inferior, 

Rectus superior. 

Rectus inferior, 

Rectus externus, 

Rectus intern us. 
Orbicularis Palpebrarum. — This muscle con- 
sists of a few fibres which surround the external 
eyelids. In the upper eyelid the fibres are very 
indistinct, but on the lower they are distinct, be- 
cause it is upon this lid that the action of the 
muscle is principally exerted. The eye is closed 
by the lower lid being drawn up. 



12 MYOLOGY OF THE PIGEON. 

Pyramidalis Nictitans. — In order to see this 
muscle it is necessary to take hold of the free edge 
of the nictitating membrane, or third eyelid, with 
the forceps and pull it backward over the eye. 
When the membrane is tense, it will be noticed 
that the free border is thicker than the rest of it. 
This thick part is really the tendon of the Pyra- 
midalis nictitans. If this tendon is followed up, 
it will be found to spring from a little muscle 
which arises from the lower internal side of the 
eyeball. It soon gives off the tendon just spoken 
of, which passes through a pulley formed by 
another muscle, called the quadratus nictitans, 
whose function is to prevent the pyramidalis 
tendon from pressing on the optic nerve in its 
action. After the tendon passes through this 
muscular pulley, it passes downward to reach the 
lower extremity of the third eyelid, to which it is 
attached along its entire free margin. The action 
of this muscle is to pull the third eyelid over the eye. 

Quadratus Nictitans is a small band of 
muscle fibres arising from the sclerotic of the 
upper side of the eye ball. Its fibres pass down- 
ward and inward to be inserted into the sheath of 
the optic nerve. The function of this muscle is to 
form a pulley for the Pyramidalis. 



THE MUSCLES OF THE EYE. 1 3 

Obliquus Superior. — The two oblique muscles 
arise close together, and will be easily recognized 
by their closely connected origins and their widely 
separated insertions. The obliquus superior arises 
from the antero-internal surface of the orbital plate 
of the frontal bone. Its fibres pass backward and 
upward to be inserted into the upper side of the 
eye ball. 

Obliquus Inferior arises close to the preced- 
ing and forms a similarly shaped muscle. The 
fibres pass backward and downward to be inserted 
into the sclerotic of the inferior surface of the eye- 
ball. 

The Recti Muscles. — The four recti muscles 
will arise from that portion of the interorbital 
septum which forms the circumference of the optic 
foramen. The superior rectis arises from the 
superior border of this margin, the fibres pass for- 
ward, upward and outward to be inserted into the 
superior border of the sclerotic. The rectus 
inferior arises from the inferior portion of the 
foramen circumference. Its fibres pass forward, 
downward and outward to be inserted into the 
inferior surface of the sclerotic. 

The rectus externus arises from the posterior 
■nortion of the foramen circumference. Its fibres 



14 MYOLOGY OF THE PIGEON. 

pass outward and backward to be inserted into the 
posterior surface of the sclerotic. 

The rectus interims arises from the anterior 
surface of the foramen circumference, and its fibres 
pass outward and forward to be inserted into the 
anterior surface of the sclerotic of the eyeball. 



PLATE I. 




Fig. 4. 



Fiq. 1. 



THE MUSCLES OE THE EYE. 



15 



Indkx to Plate I., Fig. t. Index to Plate I., Fig. 4. 



I. 


Platisma myoides. 


1. 


Flexor perforatus medius 


2. 


Digastric. 




secundus pedis. 


3- 


Masseter. 


2. 


Flexor perforatus indicis 


4- 


Stylo-hyoides. 




secundus pedis. 


5- 


Genio-hyoid. 


3- 


Flexor perforatus annulis 


6. 


Cerato-hyal. 




primus pedis. 


7- 


Rectus capitis lateralis. 


4- 


Flexor perforatus medius 


8. 


Biventer cervicis. 




primus pedis. 


9- 


Complexus. 


5- 


Flexor perforatus indicis 


10. 


Ivongus colli posticus. 




• primus pedis. 


11. 


Obliquus colli. 


6. 


Tendon of the Gastroch- 


12. 


Inter transversales. 




nemius. 


S3- 


Longus colli anticus. 


7- 


Tendon of the Flexor lon- 
gus hallucis. 






8. 


Flexor profundus digi- 
torum. 






9- 


Soleus. 






10. 


Plexor hallucis brevis. 






11. 


Extensor hallucis brevis. 






12. 


Biceps femoris. 






I3« 


External head of the Gas- 
trocnemius thrown 
back. 






14. 


Middle head of the Gas- 
trochnemius thro w n 
back. 






15. 


Internal head of the Gas- 
trocnemius thro w 11 
back. 






16. 


Adductor longus. 






17- 


Insertion of the Vastus 
extern us. 






18. 


Femur. 



1 6 MYOLOGY OF THE PIGEON. 



THE MUSCLES OF THE NECK. 

These consist of a superficial set of muscles 
which arise from the different cervical vertebrae 
and insert on the head, and of a deep set of muscles 
which connect the vertebrae with each other. 
They are the 

Biventer cervicis. 

Complexus. 

Rectus capitis posticus. 

Longus colli posticus. 

Obliquus colli. 

Rectus capitis lateralis. 

Trachelo-mastoideus. 

Rectus capitis anticus. 

Longus colli anticus. 

Inter spinales. 

Inter transversales. 
Biventer Cervicis arises partly from neigh- 
boring muscles and partly by a delicate tendon 
from the neural spine of the antepenultimate 
cervical vertebra. Its muscular origin is from the 
longus colli posticus. Its tendinous origin extends 
forward on the dorsal side of the neck in the 



THE MUSCLES OF THE NECK. 1 7 

median line, soon passing into a spindle-shaped 
belly about one and a half inches long, again 
becoming tendinous, succeeded by a second belly 
which inserts into the supra-occipital between the 
complexus and rectus capitis posticus. 

Complexus arises from the transverse processes 
of the fourth, fifth and sixth cervical vertebrae. 
This extensive origin gives the muscle good 
breadth. It is inserted at the supra-occipital 
region, its insertion extending to the posterior 
median line where it blends with its fellow of the 
opposite side. 

Rectus Capitis Posticus arises from the whole 
length of the spine of the axis, extends upward 
and is inserted below the supra-occipital margin. 
It is a thick, strong muscle found immediately 
below the complexus. Its function is to extend 
the head. 

IvOngus Colli Posticus. — This is a long muscle 
extending the whole length of the back of the 
neck. Its origin is from the neural spine of the 
ante-penultimate dorsal vertebra, and by muscular 
slips from the lamina of the cervical vertebrae as 
far forward as the seventh. At its most posterior 
origin it blends with the fibres of the longissimus 
dorsi. It extends directly forward on the back of 



1 8 MYOLOGY OF THE PIGEON. 

the neck to be inserted into the neural spine of the 
axis, blending somewhat at this place with the 
biventer cervicis. 

Obliquus Colli consists of six muscular digi- 
tations. The first or posterior digitation arises 
from the transverse process of the eleventh cervical 
vertebra and inserts into the spine of the ninth 
cervical vertebra, and so each digitation arising 
from a transverse process inserts into the spine of 
the vertebra next but one in front of it ; the 
anterior four digitations unite with the three digita- 
tions of the longus colli posticus. 

Rectus Capitis Lateralis is a triangular 
muscle situated at the front and side of the neck. 
It arises from the third, fourth and fifth cervical ver- 
tebrae, and passes obliquely upward to be inserted into 
the basi- and par-occipital regions. This muscle 
draws the head to the side and flexes it upon the 
neck. 

Trachelo-Mastoideus. — This muscle is shaped 
somewhat like the preceding and arises in common 
with it, partly overlapping it in its course. It is 
inserted into the basi-temporal bone. Its action 
is similar to that of the rectus lateralis. 

Rectus Capitis Anticus. — This is triangular 
and is situated in the front (ventral surface) of the 



MUSCLES OF THE NECK. 19 

neck. It arises from the ventral surface of the 
transverse processes and from the centrse of the 
second, third and fourth cervical vertebrae. It 
blends somewhat with the complexus and is 
inserted into the basi-temporal . 

Longus Colli Anticus is a long muscle extend- 
ing the whole length of the ventral side of the 
neck. It arises from the centrse and transverse 
processes of the posterior cervical vertebra, and 
inserts on the centrum of the atlas. The deep 
muscles of the neck are those which bind the dif- 
ferent parts and processes of one vertebra to 
another. The most important of these are : 

Inter-Spinales. — A series of muscles connect- 
ing the neural spines. They are best seen in those 
cervical vertebrae which have high spines. 

Inter-transversales is a series somewhat 
similar to the preceding, but arranged in two sets. 
One set connects the transverse processes, the other 
connects the parapophyses. These muscles afford 
protection to the vertebral artery. 



20 MYOLOGY OF THE PIGEON. 



MUSCLES OF THE PECTORAL 
EXTREMITY. 

In this group will be found certain cutaneous 
muscles lying in the alar membrane, the muscles 
forming the fleshy portion of the breast and the 
muscles of the arm. The group consists of the 

Tensor Patagii lougus, 

Tensor Patagii accessorius, 

Tensor Patagii brevis, 

Pectoralis major, 

Pectoralis secundus, 

Pectoralis tertius, 

Pectoralis quartus, 

Biceps, 

Triceps, 

Brachialis anticus. 
In taking off the skin of the breast and arm, 
the student should be careful not to remove the 
patagii muscles situated in the wing or alar mem- 
brane. 

Tensor Patagii Longus. — This is a subcu- 
taneous muscle lying in the alar membrane. Its 
muscular fibres take their origin from the antero- 
external region of the pectoralis major muscle ; it 



MUSCLES OF THE PECTORAL EXTREMITY. 21 

receives fibres from a similar muscle, the tensor 
patagii brevis, and then gives off a long tendon 
which passes through the free border of the alar 
membrane to be inserted into the skin on the pre- 
axial border of the manus. 

Tendon Patagii Accessorius. — This is also a 
subcutaneous muscle, which lies in the posterior 
region of the alar membrane. It arises from the 
bicipital fascia, and also has fascial connection with 
the tendon of the tensor patagii longus. The 
belly of this muscle is quadrilateral, and gives off 
a long tendon which passes across the alar mem- 
brane till it reaches the free border of the mem- 
brane, where it passes parallel to the tensor 
patagii longus to be inserted with it into the skin 
of the preaxial border of the manus. 

Tensor Patagii Brevis. — This muscle is 
situated on the dorsal aspect of the shoulder, con- 
sisting of a broad sheet of muscle fibres. It arises 
from the dorsal ends of the furcula and coracoid. 
It then passes backward, running alongside of, 
and partly covering, the triceps. It then has some 
connection with the tensor patagii longus, at 
which point it gives off a broad tendon, which is 
inserted into the fascia of the extensor carpi radi- 
alis longior at the elbow joint. 



22 MYOLOGY OF THE PIGEON. 

Pectoralis Major. — This is the muscle which 
forms the greater portion of the fleshy breast of the 
pigeon. It arises from the ventral part of the 
whole length of the keel of the sternum, from the 
body of the sternum and from the clavicle. It is 
closely connected with the pectoralis tertius, which 
it overlies. It is inserted by muscular fibres into 
the ventral aspect of the greater tuberosity of the 
humerus. The function of this muscle is to de- 
press the wing. 

Pectoralis Secundus (Sub-Clavius).— This is 
the bipinnate muscle, lying immediately beneath the 
muscle last described. Its fibres arise from the keel 
of the sternum and from the body of the sternum 
internal to the origin of the preceding muscle. Its 
fibres converge anteriorly, and form a round tendon 
which passes through the foramen triossium to be 
inserted on the outer side of the humerus, just 
below the insertion of the pectoralis major. The 
function of this muscle is to elevate the limb. 

Pectoralis Tertius arises from the corpus 
sterni near the costal border, and forms a strong 
tendon which is inserted into the lesser tuberosity 
of the humerus. Its fibres are closely connected 
with those of the pectoralis major, except at its 
insertion. 



MUSCLES OF THE PECTORAL EXTREMITY. 23 

PECTOralis Quartus. — This muscle is the 
smallest of the pectorals, and is situated at the 
front of the breast. It arises by two heads, one 
from the dorsal extremity of the clavicle, the other 
from the dorsal surface of the manubrium of the 
sternum. The two heads unite to form a common 
insertion into the lesser tuberosity of the humerus, 
blending with the subscapularis at this point. 

Biceps. — This is a long fusiform muscle occupy- 
ing the antero-internal aspect of the brachium. It 
arises by two heads, one from the outer aspect of 
the head of the coracoid, just beyond the glenoid 
cavity. The other head arises from the ulnar tuber- 
osity of the humerus. A common belly is formed 
whose tendon is inserted into the ulna, just in front 
and below the articular cavity. The function of 
this muscle is to flex the ante-brachium. 

Triceps. — This muscle is a large one situated on 
the inner and hinder surfaces of the arm. It con- 
sists of two distinct bellies and three heads. The 
scapula or long head arises by a tendon from the 
rounded tubercle on the outer posterior margin of 
the glenoid cavity of the scapula. It forms a 
somewhat thick flat belly, which winds around the 
shoulder joint beneath the scapular portion of the 
deltoid, runs down the postero-lateral aspect of the 



24 MYOLOGY OF THE PIGEON. 

humerus, having fascial connection with the external 
triceps. It then forms a flat tendon just above the 
elbow, where it is inserted into the radial side of the 
olecranon process of the ulna. The internal head 
arises on the inner margin of the pneumatic fossa, 
and unites below the fossa with the third or external 
head. This head of the muscle arises on the outer 
margin of the pneumatic fossa, forming a well- 
marked bifurcation to the common belly thus 
formed, the fibres of which make attachment to the 
posterior surface of the humerus, and from thence 
the muscle passes over the elbow joint to be inserted 
into the olecranon process of the ulna. The func- 
tion of this muscle is to extend the ante-brachium. 
Brachialis AnTICUS is a small muscle arising 
from the anterior and inner side of the distal ex- 
tremity of the humerus and inserting on the prox- 
imal end of the ulna immediately below the greater 
sigmoid cavity. It has the function of flexing the 
ante-brachium. 



MUSCLKS OF THK TRUNK AND PECTORAL LIMB. 25 



MUSCLES OF THE TRUNK AND 
PECTORAL LIMB. 

The muscles of this group consist mainly of the 
muscles which bind the scapula to the body. They 
are, the 

Latissimus Dorsi. 

Trapezius. 

Rhomboideus. 

Levator Scapulae. 

Serratus magnus. 

Thoracico Scapularis. 
Latissimus Dorsi is the most superficial of the 
muscles of the back in the scapular region. It 
arises from the spines of the last cervical and the 
first dorsal vertebrae, and extends as a thin band of 
muscle superficially over all the muscles of this 
region. Then it passes between the scapular and 
humeral parts of the biceps to be inserted into the 
hinder surface of the shaft of the humerus at about 
its middle. 



26 MYOLOGY OF THE PIGEON. 

Trapezius. — This muscle is found immediately 
beneath the preceding. It stretches across from 
the back to the scapula and helps to bind that bone 
firmly to the body. It arises from the neural spines 
of the last cervical and first four dorsal vertebrae, 
and inserts along the whole length of the vertebral 
margin of the scapula. 

Rhomboideus is situated immediately beneath 
the preceding and has nearly the same origin and 
insertion. It arises from the neural spines of the 
first four dorsal vertebrae. Its fibres pass obliquely 
backward to insert along the posterior two-thirds of 
the vertebral margin of the scapula and also on the 
internal surface of that bone. 

Levator Scapula is found immediately beneath 
the rhomboideus. It arises by muscular fibres from 
the transverse processes of the first two cervical 
vertebrae and inserts into the middle of the internal 
surface of the scapula. 

Serratus Magnus arises by three fleshy digita- 
tions from the second, third and fourth dorsal ribs. 
These digitations unite to form a common band of 
muscle which inserts on the lower margin of the 
distal end of the scapula. 

Thoracico Scapularis. — This is a muscle seen 
on the chest wall, anterior to the muscle just de- 



MUSCLES OE THE TRUNK AND PECTORAL LIMB. 27 

scribed. It arises by two fleshy digitations from 
the last free rib and the first dorsal rib. The two 
digitations unite to form a common belly which 
penetrates the subscapularis muscle to be inserted 
into the inner surface of the scapularis about its 
proximal fourth. 



28 MYOLOGY OF THE PIGEON. 



MUSCLES OF THE SHOULDER-GIRDLE 
AND ARM. 

The shoulder-girdle of the pigeon consists or L ae 
scapula, clavicle and coracoid. So that under this 
head we will consider the muscles that arise from 
these three bones and insert into the humerus. 
They are the 

Teres major. 

Subscapularis. 

Teres minor. 

Coraco-brachialis. 

Deltoid. 
In order to see the muscles reaching from the 
shoulder girdle to the arm, it is necessary to take 
the entire shoulder-girdle and arm from the body. 
To do this one must cut the muscles binding the 
scapula to the body. Then disarticulate the cora- 
coid from its sternal articulation and cut the clavicle 
near its sternal articulation with a pair of scissors. 
To expose the articulations of these bones the large 
pectoral muscle of the breast must be cut away 
from the sternum. These bones having been freed 
from the sternum, the shoulder-girdle and arm will 
come away from the body. 



MUSCLES OF THE SHOULDER-GIRDLE AND ARM. 29 

Teres Major. — This is the largest muscle 
attached to the shoulder-blade, or scapula. 
It arises entirely from the scapula, taking its 
origin from both the external and internal sur- 
faces of the posterior two-thirds of its length. It 
is fusiform in shape and at first sight seems to 
cover the entire outer surface of the scapula. Its 
fibres are collected into a short, strong tendon, which 
passes to be inserted into the lesser tuberosity of 
the humerus and also into the margin of the pneu- 
matic fossa. 

Subscapulars. — Still examining the external 
surface of the scapula and using the teres major 
as a landmark, the muscle which is seen imme- 
diately in front of it is the subscapularis. This 
muscle arises from both the inner and outer surfaces 
oi the proximal half of the scapula, being partly cov- 
ered over by the teres major. The fibres wind 
around beneath the inferior border of the scapula 
to the internal surface, where the fibres from the 
internal and external surfaces meet and form a short 
tendon, which passes to be inserted into the lesser 
tuberosity of the humerus in common with the 
teres minor and pectoralis quartus. The belly of 
the subscapularis is more or less divided by the 
insertion of the thoracico-scapularis. 



30 MYOLOGY OF THE PIGEON. 

Teres Minor. — Turning the scapula so that 
the internal surface may be viewed, and using the 
subscapularis as a guide, the muscle just in front of 
it is the teres minor. This muscle arises from the 
irternal surface of the anterior tip of the scapula, 
but mainly from the upper extremity of the clavicle, 
where it joins the scapula. Its fibres converge to 
form a very short tendon which is inserted, with the 
tendons of the subscapularis and pectoralis quartus, 
into the lesser tuberosity of the humerus. 

Coraco-Brachiaus. — This muscle is quite a 
large one in comparison with the muscles just ex- 
amined. It will be seen on the antero-internal sur- 
face of the coracoid bone. It arises from nearly 
the whole length of the bone and passes directly up- 
ward until it meets the tendons of the subscapularis 
and teres minor, where it gives off a small tendon 
to be inserted into the lesser tuberosity of the hu- 
merus, between the insertions of the teres major 
and subscapularis. 

Deltoid. Turn the scapula over so as to view 
the external surface. A long muscle will be seen 
arising from the anterior end of the scapula and 
passing obliquely downward to the lower end of 
the humerus. This is one portion of the deltoid 
muscle, of which there are two parts. This part 



MUSCLES OF THE SHOULDER-GIRDEE AND ARM. 3 1 

arises from the external surface of the anterior end 
of the scapula and passes down the arm to be 
inserted into the external surface of the middle 
third of the humerus. The other portion of the 
deltoid muscle arises just in front of the preceding, 
but not from the same bone. It arises from the 
upper extremity of the coracoid bone, passes over 
the shoulder joint to be inserted into the greater 
tuberosity of the humerus. 



32 MYOLOGY OF THF, PIGEON. 



Index to Plate II , Fig. 2. 

1. Head of the triceps (humeral). 

2. Extensor proprius pollicis. 

3. Extensor indieis brevis. 

4. Pectoralis major. 

5. Tensor patagii longus. 

6. Tensor patagii brevis. 

7. Biceps. 

8. Tensor patagii accessor! us. 

9. Extensor metacarpi radialis longior. 

10. Pronator brevis. 

11. Pronator longus. 

12. Flexor digitorum profundus. 

13. F'lexor carpi ulnaris brevior. 

14. Flexor digitorum sublimus. 

15. Flexor carpi ulnaris longior. 

16. Interossei. 

17. Flexor brevis pollicis. 

18. Flexor metacarpi brevis. 



MUSCLES OF THE ANTE-BRACHIUM. 33 



MUSCLES OF THE ANTE-BRACHIUM 
OR FOREARM. 

The muscles of the forearm of the pigeon con- 
sist of flexors, pronators, extensors, and supinat- 
ors. The flexors and pronators are situated on the 
inside of the forearm, while the extensors and 
supinators are on the outside of the limb. We will 
first consider the muscles on the inside of the fore- 
arm. 

In taking off the skin of the inside of the fore- 
arm, the dissector will meet with a tendinous 
band on the ulnar side extending from the internal 
condyle to the wrist. This is a part of the flexor 
sublimus muscle, and must not be removed. The 
muscles, having been separated, will be found to 
occupy the following positions from above down- 
ward : The uppermost muscle is the extensor 
metacarpi radialis longior, with its two heads. As 
it is an extensor muscle, we will consider it when 
dissecting the outside of the forearm. 

The muscle next below this is the pronator brevis, 
and immediately below this is the pronator longus. 
Below this and partly covered by it will be found 
the flexor digitorum profundus. Beneath and between 



34 MYOLOGY OF THE PIGEON. 

the last two muscles mentioned, the flexor carpi 
ulnaris brevior is situated. Below the flexor digi- 
torum profundus and partly covering it is seen the 
tendinous band spoken of above ; this is the flexor 
sublimus digitorum,and immediately beneath it will 
be found the flexor carpi ulnaris longior (Fig. 2.) 
The muscles then to be studied on the flexor side 
of the forearm, are the 

Extensor metacarpi radialis longior. 

Pronator brevis. 

Pronator longus. 

Flexor digitorum profundus. 

Flevor carpi ulnaris brevior. 

Flexor digitorum sublimus. 

Flexor carpi ulnaris longior. 
Pronator Brevis is the uppermost muscle on 
the flexor side of the forearm. It arises from a small 
tubercle above the external condyle of the humerus, 
crosses the forearm and inserts into the preaxial 
side of the shaft of the radius a short distance above 
its distal extremity. 

Pronator Longus is larger than the preceding 
and lies beneath it. It arises from the internal con- 
dyle and inserts along the whole length of the radius 
beneath the insertion of the brevis. Its function is 
not only to pronate but also to flex the forearm. 



MUSCLES OF THE ANTE-BRACHIUM. 35 

Flexor Profundus Digitorum arises by a 
fleshy head on the inner and radial surface of the 
shaft of the ulna from the insertion of the brachi- 
alis anticus to about one-half the length of the 
bone. Near the middle of the shaft of the ulna it 
terminates in a tendon running to the ulnar side of 
the carpus, passes through the fascial sheath to the 
anterior margin of the index digit and inserts into 
the base of the distal phalanx. 

Flexor Carpi Ulnaris Brevior is situated 
immediately beneath the flexor profundus, and 
arises from the lower half of the shaft of the ulna. 
The tendon winds around the radial carpal to be 
inserted into the ancholysed first metacarpal. 

Flexor Digitorum Sublimus arises from the 
internal condyle of the humerus, runs down to the 
ulnar side of the forearm and ends in a strong ten- 
don which is inserted into the ulnar carpal. The 
carnious portion of this muscle is entirely hidden 
by a tendinous band which extends from its origin 
to its insertion, and forms the real attachments of 
the muscle. A short distance above the wrist it 
gives off a short tendon which passes through a 
fibrous loop at the ulnar side of the carpus and is 
inserted into the proximal phalanx of the index 
digit. 



36 MYOLOGY OF THE PIGEON. 

Flexor Carpi Ulnaris L,ongior is that muscle 
which is situated along the inner free side of the 
ulna and forms the fleshy mass along the ulnar border 
of the ante-brachium. Its tendon of origin is short 
and originates from the internal condyle of the 
humerus. Its tendon of insertion is also short, 
ending on the ulnar carpal. 



EXTENSORS AND SUPINATORS. 37 



EXTENSORS AND SUPINATORS. 

EXTENSOR MUSCLES OF THE FOREARM. 
The muscles on the outside of the forearm when 
separated are situated in the following order. Be- 
ginning at the anterior aspect, we first have the 
long head of the extensor metacarpi radialis longior, 
and behind this we have the short head of the 
same muscle. Immediately behind this the supinator 
brevis is seen, and behind it is the extensor com- 
munis digitorum. Beneath and between the last 
two muscles mentioned, the extensor ossis meta- 
carpi pollicis makes its appearance. Behind the 
extensor communis digitorum, the extensor meta- 
carpi radialis brevior is seen. Behind this again is 
seen the muscular attachment to the ulna of the 
same muscle. (See Fig. 3.) The muscles then to 
be studied on the external or extensor side of the 
forearm are : 

Extensor Metacarpi Radialis longior, 

Supinator brevis, 

Extensor communis Digitorum, 

Extensor Ossis Metacarpi Pollicis, 

Extensor Metacarpi radialis brevior, 

Extensor Indicis- longus. 



38 MYOLOGY OF THE PIGEON. 

Extensor Metacarpi Radialis Longior is 
the principal extensor of the hand upon the fore- 
arm. It arises by two strong tendinous heads, one 
above the other ; the upper from a tubercle above 
the external condyle of the humerus, the lower 
from the tubercle of the condyle. The two heads 
unite to form a common tendon which passes in a 
well-marked groove on the distal end of the radius 
to be inserted into the anchylosed first metacarpal. 
This muscle raises the hand, and draws it forward 
toward the radial margin of the forearm and retains 
it in the same plane. 

Supinator Brevis is beneath the preceding. 
It arises from the external condyle in common with 
the lower head of the extensor metacarpi radialis 
longior. It is inserted on the outer side of the 
shaft of the radius for nearly its entire length. 

Extensor Communis Digitarum is below the 
extensor metacarpi radialis longior, arising from 
the external condyle of the humerus. Its belly is 
blended with the supinator brevis for a short dis- 
tance from their origin, and terminates in a short 
tendon which at the wrist passes through a groove 
in common with the tendon of the extensor meta- 
carpi radialis brevior, thence into a well-marked 
groove along the anterior aspect of the second 



EXTENSORS AND SUPINATORS. 39 

metacarpal nearly to the end of the latter, where 
it lies beneath the tendons of the other muscles, 
and turns to be inserted on the anterior border at 
the base of the proximal phalanx of the second 
digit. 

Extensor Ossis Metacarpi Pollicis is situ- 
ated deeply in the forearm, its origin beginning 
just below the sigmoid cavity of the ulna, from the 
upper portion of the radius and from the inter- 
osseus membrane. The muscular fibres terminate 
in a very delicate tendon which passes to the wrist 
alongside of the extensor metacarpi radialis longior 
to be inserted in the first metacarpal. 

Extensor Metacarpi Radialis Brevior is a 
large muscle on the outer aspect of the forearm, 
arising from the external condyle of the humerus. 
It has two insertions ; the first is by muscular fibres 
into the upper half of the shaft of the ulna on its 
radial side ; the second by a strong tendon which 
passes to the outer side of the distal end of the 
ulna, in common with the tendon of the extensor 
communis digitorum, to be inserted into the middle 
of the posterior edge of the second metacarpal. 

Extensor Indicis Longus arises from nearly 
the whole length of the shaft of the ulnar side of 
the radius. The small belly soon terminates in a 



40 MYOLOGY OF THE PIGEON. 

long and strong tendon, which passes over the 
groove at the distal end of the ulna in company 
with the extensor communis digitorum. It then 
continues along the superior border of the index 
metacarpal, over the proximal phalanx of the same, 
until it reaches the distal phalanx of the index 
digit, to the proximal extremity of which it inserts, 
by dividing, into two places. 



THE INTRINSIC MUSCLES OF THE HAND 41 



THE INTRINSIC MUSCLES OF THE HAND. 

The muscles of the hand are distributed upon 
its several aspects as described below, and are 
the 

Extensor proprius Pollicis. 

Extensor brevis Pollicis. 

Flexor brevis Pollicis. 

Flexor Metacarpi brevis. 

Extensor Indicis brevis. 

Flexor minimi Digiti. 

Interosseus dorsalis. 

Interosseus Palmaris. 
Extensor Proprius Pollicis is a small muscle 
which arises from the tendon of the extensor 
metacarpi radialis longior. It gives off a stout 
tendon which is inserted into the inner side of the 
pollex phalanx. 

Extensor Brevis Pollicis is an extremely 
small muscle on the outside of the hand, having 
the same function as the extensor proprius pol- 
licis, but situated on the opposite side of the hand 
from it. This small muscle arises from the first 
metacarpal bone, and gives off a delicate tendon 
which is inserted into the base of the phalanx 



42 MYOLOGY OF THE PIGEON. 

opposite the insertion of the extensor proprius 
pollicis. 

Flexor B re vis Pollicis arises from the prox- 
imal end of the second metacarpal. It has no 
tendon, but the fibres pass to insert into the whole 
length of the pollex phalanx. 

Flexor Metacarpi Brevis arises by a tendon 
from the lower extremity of the ulna. A short 
distance from its tendinous origin it forms a large 
belly, which inserts by muscular fibres into the 
third metacarpal for two-thirds its length. It 
flexes the hand upon the forearm. 

Extensor Indicts Brevis arises by muscular 
fibres from the entire length of the upper and 
inner side of the second metacarpal. It terminates 
in a small tendon which inserts into the proximal 
phalanx of the index digit. 

Flexor Minimi Digiti is a very small muscle 
which arises from the lower third of the outer 
border of the first metacarpal. It inserts by mus- 
cular fibres into the proximal end of the medius 
phalanx, which is the smallest finger of the bird's 
hand . 

The two following muscles receive their name 
from their peculiar situations between -the second 
and third metacarpals : 



THE INTRINSIC MUSCLES OF THE HAND. 43 

Interosseus Dorsaus. — This is the most ex- 
ternal of the two, and arises from the margins of 
the shafts of both these bones, the fibres converg- 
ing to form a delicate tendon which passes to be 
inserted into the base of the distal phalanx of the 
index. Its function is to extend this finger. 

Interosseus Palmaris. — This muscle is situ- 
ated beneath the muscle last described. Its fibres 
also arise from the margins of the second and third 
metacarpal bones, and its origin extends further 
down than the dorsal interosseus. It ends in a 
delicate tendon which passes to insert into the 
distal end of the distal phalanx of the index digit. 
The function of this muscle is to flex the digit. 



44 



MYOLOGY OF THE PIGEON. 



Index to Plate III., Figure 3. 



I. 


Deltoid (coracoid part of) 


1. 


Gluteus minimus. 


2. 


Deltoid (scapular part of) 


2. 


Sartorius. 


3- 


Triceps (scapular head) 


3- 


Crureus. 


4- 


Triceps (humeral head) 


4- 


Crureus. 


5- 


Extensor metacarpi radi- 


5- 


Fibres representing tensor 




alis longior. 




vagina femoris. 


6. 


Lower origin of No. 5. 


6. 


Semi-membranosus. 


7. 


Extensor communis digi- 


7- 


Semi-tendinosus. 




torum. 


8. 


Adductor longus. 


8. 


Supinator brevis. 


9- 


Gluteus medius. 


9- 


Extensor indicis logus. 


10. 


Femoro caudal. 


io' 


,10 // . Extensor metacarpi 


11. 


Accessory femoro caudal. 




radialis longior. 


I2 V 


Tibialis anticus. 


11. 


Extensor ossis metacarpi 


13- 


Peroneus longus. 




radialis brevior. 


14. 


Flexor annularis primus 


12. 


Interosseus dorsalis. 




pedis. 


13- 


Interosseus palmaris. 


IS- 


Flexor medii secundus 


14. 


Flexor brevis pollicis. 




pedis. 


15- 


Extensor brevis pollicis. 


i6 / 


16". Outer head and tendon 


16. 


Flexor metacarpi brevis. 




of gastrocnemius. 


17. 


Flexor minimi digiti. 


17- 


Tendon of flexor medius 


18. 


Tensor patagii brevis. 




primus pedis. 


J 9- 


Teres major. 


18. 


Tendon of flexor annularis 


20' 


,20". Trapezius. 




primus pedis. 


2l' 


22 ,f . Rhomboideus. 


i9 r 


19". Origin and insertion 


24. 


Serratus magnus. 




gluteus maximus. 


25- 


Pectoralis major. 


20 / 


2o v . Origin and insertion 
biceps femoris. 






21. 


Lateralis cauda. 






22. 


Levator caudae. 






23- 


Obturator externus. 




PLATE III— Fig 3. 



THE MUSCLES OF THE THORAX AND ABDOMEN. 45 



THE MUSCLES OF THE THORAX AND 
ABDOMEN. 

In this group of muscles will be found those of 
the spine, ribs and abdomen. As the spine of the 
pigeon is short and undergoes few movements, there 
is no need of many muscles. The ribs and abdo- 
men are well supplied with muscles. The group 
consists of : 

L,ongissimus dorsi. 

Sacro-lumbalis. 

Scalenus medius. 

Levatores costarum. 

Inter costales. 

External oblique. 

Internal oblique. 

Rectus abdominis. 

Transversalis abdominis. 
L,ongissimus Dorsi arises from the postero-in- 
ternal surface of the ilium and from the neural 
lamina and spines of the dorsal vertebrae. It passes 
forward as far as the eleventh cervical vertebra. It 
is bounded externally by a small band of fibres 
which represent the sacro-lumbalis. 



46 MYOLOGY OF THE PIGEON. 

Sacro-Lumbalis. — This muscle is only slightly 
developed in the pigeon, and, as in the higher 
vertebrates, is inseparably connected with the 
longissimus dorsi. It arises from the anterior mar- 
gin of the ilium and passes as far forward as the 
first dorsal rib, having attachments to all the dorsal 
ribs as it passes over their angles. 

Scalenus Medius arises by two muscular digi- 
tations from the transverse processes of the eleventh 
and twelfth cervical vertebrae. The two digitations 
join to form a common tendon which is inserted 
into the anterior margin of the free rib. 

Levatores Costarum compose a number of 
muscular slips found in a series directly behind the 
scalenus medius. The first one arises from the 
transverse process of the twelfth cervical vertebra, 
and passes downward and backward to be inserted 
into the anterior margin of the free rib. The rest 
of the levatores costarum have their origins and 
insertions in succession from the transverse pro- 
cesses of the vertebrae to the corresponding ribs. 

Inter Costales. — The intercostal muscles are 
very slightly developed in the pigeon. The set 
between the first dorsal rib and the free rib are the 
best developed. The external intercostal here arises 
from the first dorsal rib as far down as its insertion 



THE MUSCLES OF THE THORAX AND ABDOMEN. 47 

into the sternum, the fibres pass obliquely upward 
and forward, and are inserted into the unciform 
process of the free rib. The internal intercostals 
are very slightly formed. They have the same 
points of attachment, but the fibres pass in the oppo- 
site direction. 

The abdominal muscles consist of the external 
and internal oblique, the transversalis abdominalis, 
and the rectus abdominalis. 

The External Oblique arises by an aponeuro- 
sis from the external surface of each of the dorsal 
ribs at a line corresponding to the borders of the unci- 
form processes. Also by aponeurosis from the inferior 
margin of the ilium and pubis. The fibres pass 
obliquely forward and inward to the median line, 
where in the abdomen the muscle unites with its 
fellow of the opposite side at the linea alba. The 
thoracic portion of this muscle is inserted into the 
sides and xiphoid process of the sternum. 

The Internal Oblique is found immediately 
below the external oblique. It arises from the 
inferior margin of the ilium. The fibres pass for- 
ward in a radiating manner to be inserted into the 
posterior border of the last dorsal rib. 

Rectus'Abdominis arises by aponeurosis from the 
whole length of the pubis. The aponeurosis con- 



48 MYOLOGY OF THE PIGEON. 

tinues some distance along the abdomen, but soon 
develops into muscular fibres which pass directly to 
the xiphoid process of the sternum. 

TransvERSAUS Abdominis arises by aponeuro- 
sis from the inferior border of the ilium and pubis . 
The fibres pass obliquely across the abdomen to the 
linea alba, where the muscle meets its fellow of the 
opposite side. Anteriorly it attaches to the poster- 
ior margin of the last rib. 



MUSCLES OF THE TRUNK AND THIGH. 49 



MUSCLES OF THE TRUNK AND THIGH. 

In this group will be found those muscles which 
arise from the different parts of the pelvis and 
insert into the thigh and leg. They consist of the 
gluteal muscles, three in number : the biceps 
femoris, the femoro-caudal and accessory femoro- 
caudal, the obturators and gemellus muscle, the 
adductors magnus and longus, the extensors 
femoris and sartorius, the semi-tendinosus and semi- 
membranosus. 

These muscles will be most conveniently dis- 
sected in the following order. 

Gluteus maximus. Sartorius. 

Gluteus medius. Extensor femoris. 

Gluteus minimus. Vastus externus. 

Biceps femoris. Vastus interims. 

Femoro-caudal. Semi-tendinosus. 

Accessory femoro-caudal. Semi-membranosus. 

Obturator externus. Adductor longus. 

Obturator internus. Adductor magnus. 

Gemellus. Ambians. 



5<D MYOLOGY OF THE PIGEON. 

When the skin is taken off the back and thigh, 
the first exposed is a broad sheet of muscle cover- 
ing nearly all the muscles mentioned above. It 
represents the tensor vaginae fern oris, and the 
gluteus maximus of the higher vertebrates ; but 
will be described here simply as the gluteus 
maximus. 

Gluteus Maximus takes its origin by a thin 
fascia from the entire outer surface of the ilium. 
The muscle continues as a broad sheet of fascia till 
it reaches the prominence of the hip, where it 
begins to develop muscle fibres which are exten- 
sive at the posterior portion of the muscle, but thin 
at the anterior portion. The width of the muscle 
in the thigh extends as far forward as the posterior 
border of the sartorius and as far back as the pos- 
terior border of the biceps which it covers. As 
the fibres pass down towards the knee they con- 
verge to form a broad aponeurosis, which is con- 
tinuous with the aponeurosis of the extensor 
femoris. This aponeurosis covers the front of the 
knee and is inserted into the cnemial crest of the 
tibia. 

Gluteus Medius. — This muscle is found 
beneath the fascial origin of the gluteus maximus, 
which must be cut away to expose it. It arises 



MUSCLES OF THE TRUNK AND THIGH. 5 1 

from the external concave surface of the ilium in 
front of the acetabulum. The fibres converge to 
form a flat muscular tendon which passes to the 
outer surface of the femur to be inserted into the 
great trochanter. 

Gluteus Minimus. — This is the smallest of the 
gluteal muscles and is situated anterior to and 
below the muscle last described. It arises partly 
from the outer surface of the anterior portion of 
the ilium and, by muscular fibres, from the proxi- 
mal and external portion of the first rib. The 
fibres pass backward, downward and outward to 
form a tendon which is inserted into the outer sur- 
face of the femur just below the great trochanter. 

Biceps Femoris is the large muscle found 
immediately below the gluteus maximus, and arises 
from the post-acetabular ridge of the pelvis. Its 
origin here is a broad one and the fibres extend 
directly down the leg, converging near the knee to 
form a round tendon, which passes through a ten- 
dinous loop to be inserted into the upper extremity 
of the fibula. It is also connected by fascia to the 
outer head of the gastrochnemeus. 

Femorocaudal. — After cutting the biceps and 
throwing it back, the femoro-caudal is exposed, 
which lies immediately beneath it. This is a 



52 MYOLOGY OF THE PIGEON. 

narrow ribbon-like muscle arising from the pos- 
terior portion of the pygostyle. It passes obliquely 
across the side of the pelvis to insert into the pos- 
terior surface of the proximal end of the femur. 
As it passes over the obturator externus muscle it 
receives the fibres of the accessory femoro-caudal, 
which is inserted with it. 

Accessory Femoro-caudau arises from the 
concavity on the posterior portion of the ilium 
behind the acetabulum. Its fibres pass forward to 
blend with those of the femoro-caudal, and to be 
inserted with it. 

Obturator Externus. — This muscle is found 
immediately beneath the femoro-caudal. It arises 
from the greater portion of the large concavity 
found on the external surface of the pelvis, 
and from the border of the ischiatic foramen. The 
fibres converge to form a broad flat tendon, which 
is inserted into the femur just below the great 
trochanter. 

Obturator Internus. — Only the tendon of 
this muscle can be seen on the outside of the 
pelvis. It arises from the ventral surface of the 
pelvis, from the margins of the ischiatic foramen 
and from the ischium itself. The fibres converge 
to form a strong tendon, which passes through the- 



MUSCLES OF THE TRUNK AND THIGH. 53 

obturator foramen to be inserted with the gemellus 
muscle into the trochanter of the femur. 

Gemellus. — This muscle will be seen lying 
alongside of the tendon of the obturator internus. 
It is a very small one, and takes its origin from a 
small fossa between the acetabulum and the obtu- 
rator foramen on the outside of the pelvis. Its 
fibres blend with the tendon of the obturator inter- 
nus, and are inserted with it into the trochanter of 
the femur. 

Sartorius. — This is the most anterior of the 
muscles reaching from the trunk to the leg. It is 
a strong muscle, possessing the same width through- 
out its entire length. It arises from the anterior 
external surface of the ilium and from the dorsal 
surface of the proximal end of the last rib. It 
passes directly down the front of the thigh till it 
reaches the knee-joint, where it terminates in fascia 
which pass the knee-joint and insert into the inner 
cnemial crest of the tibia. 

Extensor Femoris. — This muscle is composed 
of two distinct portions. The larger portion cor- 
responds to the rectus femoris of higher vertebrates, 
and the smaller one to the crureus muscle. The 
larger portion, or rectus femoris, covers the entire 
front and part of the external surface of the femur, 



54 MYOLOGY OF THE PIGEON. 

and arises from the whole length of that bone as 
far up as the great trochanter. The smaller por- 
tion, or crureus, arises from the upper half of the 
antero-external surface of the femur. These two 
muscles fuse with the gluteus maximus, and ter- 
minate in a tendinous fascia which spreads out over 
the front of the knee-joint, envelopes the patella 
and is inserted into the cnemial crest of the tibia. 

Vastus Externus arises from the lower two- 
thirds of the outer surface of the femur. The 
muscle gets broader as it passes down the bone, and 
at the lower extremity partly envelops the bone. 
It also ends in the fascia of the knee in conjunction 
with the gluteus maximus and rectus femoris. 

Vastus Internus arises from the inner and 
hinder aspect of the femur, at the lower two-thirds 
of that bone. It becomes larger as it approaches 
the knee, where it forms a broad tendon which 
passes over the joint to insert into the inner side 
of the head of the tibia. 

Semi-Tendinosus lies beneath and posterior to 
the biceps femoris. It arises from the ilium pos- 
terior to the acetabulum and above the ilio-sciatic 
foramen. It passes down the outside of the thigh 
to a point just beyond the knee-joint, where it ter- 
minates in a delicate fascia which inserts into the 



MUSCLES OF THE TRUNK AND THIGH. 55 

fascia of the gastrochnemeus. This muscle re- 
ceives accessory fibres which spring from the lower 
extremity of the femur and pass backward to meet 
the fascia. 

Semi-Membranosus. — This muscle is found 
immediately beneath the semi-tendinosus. It is 
much smaller than the above, and arises from the 
posterior two-thirds of the ischium. The muscle 
is long and flat, terminating in a flat tendon which 
is connected with the fascia of the internal head of 
the gastrochnemeus. 

Adductor I^ongus. — This is a large muscle 
arising from the lower margin of the ischiatic fossa. 
It passes obliquely down the back of the thigh and 
inserts into the posterior aspect of the femur for 
nearly its whole length. 

Adductor Magnus. — This is a much narrower 
muscle than the preceding, having a similar origin, 
but situated more posteriorly. It passes down the 
back of the thigh to be inserted into the linea aspera 
of the femur down as far as the internal condyle. 

AmbiENS. — This is a very delicate muscle which 
rises from the ventral margin of the ilium from a 
point just in front of the acetabulum. The fibres 
form a very thin muscle which passes down the 
inner side of the thigh, parallel to the femur. Just 



56 MYOLOGY OF THE PIGEON. 

before it reaches the knee-joint it terminates in a 
delicate tendon which enters the knee-joint and 
passes between the fascia of the knee-joint and the 
patella across to the outside of the knee, where it 
dips down between the muscles of the upper and 
outer side of the tibia. The tendon then passes 
to blend with the tendinous origin of the flexor in- 
dicis primis pedis, which we will find inserts into 
the first phalanx of the index toe. So that in the 
two muscles mentioned we have formed a system 
which extends the whole length of the leg. This 
arrangement is such that when the bird goes to roost 
at night, the weight of the body draws the muscle 
tight, and thus flexes the toe so as to take a tight 
grip upon whatever the bird may be resting. 



THE MUSCLES OF THE FRONT OF THE LEG. 57 



THE MUSCLES OF THE FRONT OF 
THE LEG. 

The muscles occupying the front of the leg are 
of two kinds. Those which extend the toes and 
which either extend or flex the tarso-metatarsus on 
the leg. In the first set there are two muscles, the 
flexor longus digitorum and the flexor brevis hal- 
lucis. In the second set there are also two muscles, 
the tibialis anticus and the peroneus longus. 

Tibialis anticus. 

Extensor longus digitorum. 

Peroneus longus. 

Extensor hallucis brevis. 
Tibialis Anticus is the large muscle occupying 
the front of the le^. It arises from the front sur- 
face of the upper third of the tibia and forms a 
large fusiform muscle which terminates in a tendon 
at the lower third of the leg. This tendon passes 
beneath the oblique ankle ligament to be inserted 
into the front surface of the upper extremity of the 
tarso-me tatarsus. 



58 MYOLOGY OF THE PIGEON. 

Extensor Eongus Digitorum is a delicate 
spindle-shaped muscle found immediately beneath 
the tibialis anticus. It arises from the anterior sur- 
face of the upper third of the tibia^ and soon 
forms a long delicate tendon which passes down the 
front of the tibia until it reaches the ankle-joint, 
where it passes beneath the bony bridge on the an- 
terior surface of the lower extremity of the femur 
between the condyles. Then the tendon passes 
down the front of the tarso-metatarsus to the 
bases of the digits, where it divides into three 
tendons, which go to the proximal ends of the 
distal phalanges of the three outer digits. The 
main tendon receives a few accessory fibres arising 
from the front of the tarso-metatarsus. 

Peroneous Eongus arises from the upper two- 
thirds of the outer side of the tibia and from the 
whole length of the fibula. At the lower third of 
the leg it terminates in a strong tendon which, 
when it reaches the external ankle, bifurcates, 
sending a short tendon to the outer side of the 
tibial cartilage and another down the side of the 
tarso-metatarsus to join the tendon of the flexor 
medii primus pedis. 

Extensor Hallucis Brevis arises from the 
antero-internal surface of the tarso-metatarsus. 



THE MUSCLES OF THE FRONT OF THE LEG. 59 

At the lower third of the bone it terminates in a 
delicate tendon which soon divides into two, the 
long one passing along the dorsal surface of the 
hallux phalanges to be inserted into the proximal end 
of the distal phalanx. The short tendon is inserted 
into the dorsal surface of the proximal phalanx. 



6o MYOLOGY OF THE PIGEON. 



THE MUSCLES OF THE BACK OF THE 
LEG. 

The muscles of the back of the leg are mainly 
flexor muscles. In the pigeon we have two flexor 
tendons going to the hallux and ring toes, and 
three to the index and middle toes. As in mammals, 
the superficial tendons are the shortest and divide 
at their insertion to let the deeper tendons pass 
through to their point of insertion. The three 
outer toes receive their deepest tendon from the 
flexor profundus digitorum, but the hallux has its 
own deep flexor, the flexor longius hallucis. Where 
there are three tendons going to one toe, I have 
used the name primus for the most superficial, and 
for the next beneath it secundus (after Shufeldt). 
The deepest tendon in such a case is always a division 
of the flexor profundus digitorum, ?'. e. , the most 
superficial muscle going to the middle toe would 
then be called the flexor medii primus pedis. 

The most superficial muscle on the back of the 
leg is the gastrochnemeus. The gastrochnemeus, 
soleus and tibialis posticus are muscles which do 



THE MUSCLES OF THE BACK OF THE LEG. 6 1 

not reach the toes, but have the function of extend- 
ing the tarso-metatarsus. I describe them in the 
order in which the dissector will find them. 

Gastrochnemeus. 

Flexor perforatus medii secundus Pedis. 

Flexor perforatus indicis secundus Pedis. 

Flexor perforatus annularis primus Pedis. 

Flexor perforatus medii primus Pedis. 

Flexor perforatus indicis primus Pedis. 

Flexor longus Hallucis. 

Flexor profundus Digitorum. 

Soleus. 

Tibialis posticus. 

Flexor brevis Hallucis. 
Gastrochnemeus arises by three heads, one from 
the external condyle of the femur, one from the in- 
ternal condyle, and one from the upper inner summit 
of the tibia. All three heads eventually form a 
common tendon which passes over the metatarsal 
joint and inserts into the hypo- tarsal process of the 
tarso-metatarsus. 

Flexor Perforatus Secundus Medii Pedis 
arises from the outer side of the head of the tibia 
and by a tendinous origin from the fibula below ; 
the fibres terminate in a strong flat tendon which 
passes through the tibial cartilage, thence along the 



62 MYOLOGY OF THE PIGEON. 

back of the tarso-metatarsus to pierce the tendon 
of the basal phalanx and to be inserted into the 
second joint of the middle toe. 

Flexor Perforates Indicis Secundus Pedis 
arises from the external condyle of the femur in 
common with the external head of the gastroch- 
nemeus ; its thin tendon passes obliquely across 
the back of the leg, through the tibial cartilage, 
down to the back of the tarso-metatarsus. From 
thence it passes to be inserted into the second 
phalanx of the index digit, being perforated by 
the tendon of the flexor profundus. 

Flexor Perforatus Annularis Primus Pedis 
arises from the posterior surface of the femur 
between the condyles, and by fascia from the 
fibula. It blends with the fibres of the flexor 
medius primis pedis. The fibres then give off a 
flat tendon which passes along the back of the leg 
in common with the flexor medius primis pedis. 
The tendon then passes through the tibial carti- 
lage, to pass along the back of the tarso-meta- 
tarsus. From thence it passes along the underside 
of the last toe, to be inserted by tendinous slips 
into each side of the basal phalanx. 

Flexor Perforatus Medii Primus Pedis 
arises from the inner side of the belly of the muscle 



THE MUSCLES OF THK BACK OF THK LEG. 63 

last described. It also has another fleshy origin from 
the belly of the flexor primus indicis pedis. The 
tendons of these two origins unite to form one 
common tendon, which passes through the tibial 
cartilage, then along the posterior surface of the 
tarso-metatarsus to the ulnar side of the basal 
joint of the third toe, to which it sends down two 
tendinous slips to either side of the phalanx. 

Flexor Perforatus Indicis Primus Pedis. — 
This muscle arises by a thin tendon from the 
hinder surface of the external condyle of the 
femur, and also from the upper and posterior part 
of the tibia. The fibres converge to form a long 
tendon which pierces the tibial cartilage. From 
thence the tendon takes the course of the other 
tendons piercing the tibial cartilage, down to the 
back of the tarso-metatarsus till it reaches the 
under side of the index toe, where it divides and 
inserts into the sides of the first phalanx, being 
perforated by the tendons of the flexor indicis 
secundus pedis and the flexor profundus digitorum. 

Flexor Longus Hallucis is found immediately 
beneath the flexor indicis primus pedis. It arises 
from the posterior aspect of the femur between the 
condyles, and from the external condyle. The 
tendon passes through the tibial cartilage, and 



64 MYOLOGY OF THE PIGEON. 

then passes around the accessory metatarsal bone, 
to be finally inserted into the proximal end of the 
ungual phalanx of the hallux. In order to get to 
the ungual phalanx, it has to pass through the 
tendon of the flexor brevis hallucis, which is 
attached to the proximal phalanx. 

Flexor Profundus Digitorum is the deepest 
of all the muscles of the back of the leg. It arises 
on the posterior aspect of the tibia and fibula for 
nearly their entire length. Near the ankle joint 
it forms a strong tendon which pierces the tibial 
cartilage and runs down the hinder surface of the 
tarso-metatarsus close to the bone. At the lower 
end of the bone it divides into three tendons, 
which go to the distal phalanx of the second, third 
and fourth toes respectively. 

Soleus lies immediately beneath the internal 
head of the gastrochnemeus. It arises from the 
posterior surface of the head of the tibia, and ter- 
minates in a long, slender tendon which is inserted 
into the tibial cartilage at its inner proximal end. 

Tibialis Posticus arises from nearly the whole 
length of the shaft of the fibula, from the posterior 
surface of the tibia and the interosseous membrane. 
It ends in a strong tendon which passes on the 
outer side of the ankle joint, to be inserted into 



THE MUSCLES OF THE BACK OF THE LEG. 65 

the proximal end of the tarso-metatarsus on its 
outer side. 

Flexor Hallucis Brevis is a small muscle 
arising by a small belly from the posterior surface 
of the head and shaft of the tarso-metatarsus. It 
sends off a delicate tendon which passes around 
the tuberosity on the proximal end of the proximal 
phalanx to the ventral side of that bone, where it 
divides to admit the passage of the tendon of the 
flexor longus hallucis. The two divisions of the 
tendon insert on the sides of the proximal phalanx 
of the hallux. 



66 MYOLOGY OF THE PIGEON. 



THE MUSCLES OF THE TAIL 

The muscles of the tail are in two sets. Those 
which insert on the tail bones and perform the 
movements of the bony tail. And those which 
insert on the butts of the tail feathers and control 
their movements. They consist of : 

Levator coccygis. 

Levator caudae. 

Lateralis caudse. 

Depressor caudse. 

Depressor coccygis. 
Levator Coccygis arises from the posterior 
extremity of the dorsal surface of the ilium. Its 
fibres pass backward and terminate in a small 
tendon, which is inserted into the dorsal surface 
of the pygostyle. 

Levator Cavd^ is a small muscle situated just 
outside the muscle just described. It arises from 
the dorsal surface of the last two caudal vertebrae. 
It is inserted into the ends of the quills of the 
rectrices feathers. 



the: muscles of the tail. 67 

IvATERALis Caudle arises by muscular fibres 
from the last three caudal vertebrae. It is flat at 
its origin, but soon develops into a round belly, 
which inserts into and envelopes the bursa Fabricii 
on the side of the pygostyle. 

Depressor Caudle is a conical muscle arising 
from the whole length of the superior border of 
the ilium. Its fibres converge as they reach the 
the tail, to insert into the ends of the external 
rectrices. 

Depressor Coccygis is a fleshy mass of muscle 
fibres lying beneath the caudal vertebrae. It 
arises from the ventral surface of the ischium, 
passes backward to the tip of the tail along the 
under surface, and finally inserts into the ventral 
surface of the side of the pygostyle. 



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